A moisture separator reheater (MSR) installed in a nuclear power plant, etc., has two functions: a function that removes moisture in moist steam exhausted from a high pressure turbine; and a function that reheats the steam to be heated, from which the moisture has been removed, through heat exchange with heated fluid. For example, as the heated fluid, main steam from a steam generator, extraction steam of a high-pressure turbine, or the like is used. The steam to be heated that has been reheated in the moisture separator reheater is supplied to a low pressure turbine, etc.
In a case where a configuration in which a heater header is provided outside a body drum is applied to the moisture separator reheater as a design of a pressure vessel, an opening portion penetrating the body drum is generally formed into a circular shape. On the other hand, a horizontal cylindrical type heater header is generally installed inside the body drum. In recent years, strength analysis technology enables a design of a structure having an opening portion having a shape other than the circular shape.
With regard to such a moisture separator reheater, there is known a technology disclosed in, e.g., Japanese Patent Application Laid-Open Publication No. 2010-60222. According to this technology, a partition plate is installed inside the body drum. A position of the partition plate is determined depending on a position of the heater header or position of U-shaped bent tube parts of a tube bundle. The partition plate prevents the steam to be heated from flowing to a portion (hereinafter, referred to as “ineffective portion”) at which the heated fluid does not contribute to heat exchange, such as a portion where no heat exchanger tube exists or the U-shaped bent tube part of the tube bundle.
Moreover, in a technology disclosed in Japanese Patent Application Laid-Open Publication No. 2011-94839, two heater headers arranged in a vertical direction are mounted to one side of the body drum. Also in this case, there is a need to install the partition plate inside the heater header.
However, in the above-described conventional moisture separator reheater, installation of the partition plate in the body drum may generate a space like the above ineffective portion that is not utilized for the function of the moisture separator reheater. This may increase a length of the tube bundle for ensuring a required heat transfer area, resulting in an increase in size of the moisture separator reheater. Moreover, under the circumstances where the size of the moisture separator reheater tends to increase with an increase in output power of the nuclear power plant, the sizes of constituent devices need to be reduced.
Embodiments of the present invention have been made in view of the above situations, and an object thereof is to provide a moisture separator reheater capable of ensuring a required heat transfer area with short heat exchanger tubes to thereby allow reduction in the size thereof, and a nuclear power plant having such a moisture separator reheater.